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COUNTROWS with VALUES: A Faster Alternative to DISTINCTCOUNT in DAX

The core principle in Power BI Data Analysis Expressions (DAX) is that combining `COUNTROWS` with either the virtual table returned by `VALUES()` or a logical `DISTINCT` flag provides a high-performance alternative to standard distinct counting mechanisms. This mechanism relies on filter-context propagation where unique values are identified and counted without materializing intermediate tables, thereby optimizing computational efficiency over traditional direct distinct count operations in relational data modeling.